Processes of treating hydrocarbons



wuwzmi 35x5 INVENTOR HAROLD v ATWELL BY M 2x44 H v. ATWELL PROCESSES OF TREATING HYDROCARBONS Original Filed Janf 23, 1934 QERkMA-Qk May 30, 1939 mum/byw- ATTORN EY Patented May 30, 1939 UNITED STATES 2,160,774 PROCESSES OF TREATING HYDROCARBONS Harold V. Atwell, White Plains, N. Y.,

Gasoline Products Company, Inc.,

assignor to Newark,

N. J., a corporation of Delaware Application January 23, 1934, Serial No. 707,867 Renewed January 25, 1936 This invention relates to processes for converting relatively heavy higher boiling hydrocarbon oils intolighter lowerboiling hydrocarbon oils such as motor fuel, and pertains more particularlyto processes for the production of relatively high anti-knock motor fuel from heavier oils, wherein provision is made for reacting any fixed gases or other hydrocarbons lighter than desired in gasoline, with heavier products to form final desired distillate.

It is an object of my invention to provide an improved process whereby relatively heavy oil is first subjected to a cracking operation wherein lighter products in the desired boiling range, for example in'the gasoline boiling range, are produced, as well as heavier products and also mainly gaseous hydrocarbons, which are of such low boiling point as to be undesirable in the final prod: uct; and wherein these mainly gaseous hydrocarbons are mixed with products too heavy for inclusion in the final desired product, and subjected to heat treatment, whereby additional quantities of final desired products are formed, as well as hydrocarbons heavier than desired in the final product and suitable for cracking to make high anti-knock gasoline or other-desired relatively light hydrocarbons.

In accordance with my invention the products of any cracking operation, preferably a high crack per pass cracking operation or a reforming operation, are fractionated in the conventional manner to yield a desired distillate and a potential cycle stock in the gas oil boiling range. This cycle stock oil is passed to a separate reverting zone such as heating coil, with or without a soaking drum, wherein it is contacted with gas containing olefins, such as uncondensed gas from the main cracking operation, under conditions favoring a reaction between the gas and the oil. Preferably high pressure such as 1000 pounds per square inch or more, and a moderate temperature such as 800 to 950 F., will be used in this stage, although lower pressures may be used if desired. Under these conditions the naphtenic, and to some extent the olefinic liquids, will react with the olefinic gas to make additional liquid hydrocarbons. At the same time the parafflnic constituents of the chargingstock will be cracked to lighter products, e. g. those in the gasoline boiling range. In the separating zone handling the emuent from the reverting zone' or heating coil, which treats the cycle stockand gas, the light products from the cracking of paraflinic components -are passed overhead and subjected to fractionation.

Heavy reversion products resulting from the re- 19 Claims. (01. 196-48) action of olefinic gas with the non-parafiinic components of the charging stock are removed from a lower point in the fractionating zone and cracked in a separate operation. Further cracking ispreferably accomplished in a separate coil, although optionally in the same furnace with the other coil, so that optimum cracking conditions may be applied to these reversion products.

Optionally the reversion products may be recycled to the main cracking operation. A product of this cracking of reversion products will be a high anti-knock gasoline which can be blended with the distillate from the main cracking coil. The products from the intermediate or reversion stage may be subjected to additional fractionation for the separation of the heaviest fraction, in case it is found difficult to limit the reaction so that the total product is crackable as a clean stock. In this case, a relatively light gas oil cut, heavier than that desired for the final product, may be separately removed and recycled to the initial cracking zone, while heavier reaction products may be passed through a separate cracking zone.

The above mentioned and further objects and advantages of my inventiomand the manner of attaining them, will be made clearin the followingdescriptiontaken in conjunction with the accompanying drawing.

. In the drawing the single figure illustrates d'iagrammatically an apparatus for carrying out the process of my invention.

Referring more particularly to the drawing, reference numeral l indicates a charging line from which fresh charging stock, such, for example, as clean gas oil, is forced by pump 2 through the coils of cracking-furnace 3, wherein it is subjected to a conventional cracking operation. This cracking operation 's preferably carried out in the vapor phase at relatively high cracking temperature, whereby relatively high anti-knock gasoline is formed, the cracking temperature preferably being above 900 F., for example, about 1000 F. The pressure is preferably relatively low, for example from to 400 poundsper square inch, most desirably to 225 pounds per square inch. From the cracking furnace 3the cracked products pass through pipe 4 into reac-' tion chamber 5 wherein further conversion thereof takes place in the usual manner. The cracking to products in the gasoline boiling range, per past, may be in the neighborhood of 15% to 25% or more. When a very clean charging stock is used the cracking per pass may be' raised to as high as 40% or 50%, or more, by providing high contact. The resulting soaked or digested products travel through pipe 6 into evaporator 7 wherein vapors separate from liquid residue in the well known manner, the residue being drawn ofi' through line 8 and the vapors passing overhead through line 9 into fractionator in. In the fractionator ID the vapors are subjected to fractional condensation in the usual well known manner, the fractionated vapors of desired boiling characteristics passing off from the top of the fractionator through pipe ll into condenser H from which the resulting condensate passes to the receiving drum l3. This drum is provided with a draw-off pipe I 4 for removing 'the finished products, e. g., gasolineand with a gas draw-off line l5 having compressor which forces the gas into a pipe H, in mixture with reflux condensate withdrawn from the bottom of the fractionator l0 through pipe l6.

Additional gas of a similar nature or richer in olefins or reactive oil, or both, may be introduced from an external source through the valved line H, if desired, in order to establish balanced conditions of operation. Alternatively part of the gas may be diverted from the process through line 72, or the gas may be freed from undesired con-- stituents, e. g. hydrogen and methane, by being passed through a separating apparatus, shown diagrammatically at 13, the undesired constituents being diverted from the process through valved line 14 while the'rest are returned to the line [5. Reference numerals I5 and 16 indicate pipes for conducting the gas to and from the separating apparatus and numerals ll, 18 and 19 refer to control valves.

The reflux condensate is forced by pump l9 in mixture with the gas from line l5 through the coils of reverting furnace I 8.- In this reverting furnace the mixture is preferably raised to a temperature in the neighborhood of 900 F. under a pressure which may vary considerably, but which is preferably in the neighborhood of 1000 pounds per square inch or more. The temperature may range suitably from 850 to 900 F., for example, while the pressure may extend from 200 pounds per square inch upward. The exact conditions of temperature and pressure selected for the reversion operation would depend upon the character of the reflux condensate and of the gas supplied to the reverting zone as well as the respective quantities thereof. In general it may be said that the richer the gas is in olefins, the lower the temperature and pressure that may be used in the reverting zone. High concentration of naphthenes in the reflux condensate favors the reaction and so where the concentration of such naphthenes is relatively high the temperature and pressure in the reverting zone may be reduced. Increased pressure in the reverting zone favors the reaction and therefore an increase in pressure tends to produce better results, other factors being equal. The products from the furnace l8 pass through pipe 2| into reactionchamber 22 Wherevapors move upwardly through the evaporator,

' being partially fractionated if desired by action of cooling coil 21., which may be supplied with cooling fluid from any suitable source, the vapors remaining uncondensed passing off from the top 2,160,774 temperatures and-pressures and short times of of the evaporator, through vapor line 28 into fractionator 29. a

In this fractionator the vapors undergo fractionation in the usual well known manner, cooling for causing the necessary refluxing action being supplied by means of cooling coil 30, or in any other suitable manner. The vapors remaining uncondensed at the top of the fractionator and having the desired boiling characteristics, pass off through vapor line 3| and condenser 32, resulting condensate being collected in the receiv ing drum 33. This drum has the usual gas drawoff line 33 and distillate draw-01f line 35, through which the distillate may be withdrawn from the process separately if desired. As a result of the fractionating taking place in the fractionator 29 a relatively heavy reflux condensate is collected in the base of the fractionator which is passed preferably through line 36 to the cracking furnace 39 by action of pump 38, although any desired portion of thisheavier reflux condensate may be withdrawn from the process through line 80. The heavy, condensate so collected would consist largely of products of the gas reversion operation having a relatively low hydrogen to carbon ratio, this condensate being especially adapted for the production of high anti-knock asoline.

, As a result of the reaction taking place in the reverting zone a portion of the paraflinc hydrocarbons supplied may pass through substantially unchanged and should be separated by fractionation and returned to the initial cracking zone. This may be accomplished by placing in the fractionator 29 an intermediate-trap-out tray 8| which serves to collect a relatively light reflux condensate, e. g. of a light gas oil nature, which may be returned through line 82, by action of pump 83, to the cracking furnace 3 for further cracking.

In case all of the reflux condensate is withdrawn from tray 8! through line 82, cooling may be supplied below the'trap-out tray in any well known manner as by directly introducing a cooling oil.

The cracking furnace 39 is preferably operated so as to heat the oil passing therethrough to a moderately high cracking temperature, of, for example, from 850 to 950 F., under a moderate pressure of, for example, 200 pounds per square inch to 400 pounds per square inch. The resulting cracked products pass through line 40 to the evaporator I along with the cracked products from the reaction chamber 5, the valve 84 being open and the valve 85 being closed.

If desired, a separate evaporator 49 may be furnished for separating the cracked products from 39 into vapors and liquids, the separated vapors passing to fractionator l0.

The pressure in the evaporator I need not be limited strictly to some fixed value, but is more suitably about 200 pounds per square inch. Highbase'of reaction chamber 5 so that any liquid which may collect from time to time may be drawn off. Ordinarily where soaking is accomplished in the vapor phase this draw-off line would not be used. Valves 45, 46 and 41 are interposed in their respective pipes so that the reaction chamber 22 may be cut out of operation if desired, thereby permitting the products from furnace l8 to pass directly through line 24 into the evaporator tower 25.- The pressure in the evaporator 25 may be regulated with-respect to that in the reverting furnace l8 by'means of valve 48. The pressure in the evaporator tower is preferably about 200 pounds per square inch. The cooling supplied to the evaporator 25 by action of cooling coil 21 is preferably so regulated that the vapors passing overhead have boiling characteristics corresponding to an end point of from 700 to 800 F. The reflux condensate removed from the base of fractionator 29 would therefore have an end point of from 700 to 800 F., approximately, While the end point of any condensate removed from the trap-out tray 8| would be less, for example 500 to 700 F. Any products too heavy for further cracking in the furnace 39 may be prevented from entering the fractionator 29 by increasing therefiuxing action caused by the cooling coil 21.

The preceding operation is normally carried out with valve 85 closed and valve 84 open, but;

when desired, valve 84 may be closed and Valve 85 opened thereby causing the cracked products from cracking furnace 39 to pass through pipe 4' and control valve 48I into evaporator 49 wherein vapors separate from liquid residue. The liquid residues may be withdrawn separately through line 50 and the vapors may be passed overhead through vapor line 5| into thefractionator l0. This arrangement permits the tars from evaporator I and evaporator 49 to be separately eliminated, an advantage since the tars may have different characeristics. This operation is per'mited when valve 52 is closed, and valve 53 opened, but if desired the valve 53 may be closed and valve 52 opened, thereby passing the vapors from the evaporator 49 through line '54 into the fractionator 55, wherein they are subjected to fractionation separately from the products in fractionator I0. This fractionation is carried out in the usual well known manner with the fractionated vapors passing off through vapor line 56 and condenser 51, the resulting condensate being collected in receiving drum 58. The distillate from receiving drum 58, e. g., gasoline, may be separately diverted from the process through valved line 59, or may be blended with the distillate collected in receiver l3, by utilization of cross-over line 50, and proper manipulation of valves GI, 62 and 63. The reflux condensate from fractionator 55 is preferably returned through valved pipe 64, by action of pump 65,

into line I'I leading to the reverting furnace I8,

7 in any desired quantity, any excess of reflux condensate being divertedfrom the process through valved pipe. The tars .withdrawn from the evaporator I, evaporator 25 and evaporator 49 may be withdrawn from the process separately or in any desired admixture either for use as a commercial product, for flashing or any other well known treatment. Distillate collected in receiver 33 may be blended with distillates from receivers I3 and 58, or either of them, as desired, by way of conduit 86. Gases from receiver 58 may be passed through line 51, by action of pump 68, into line II, for further reversion, or alternatively be first freed of undesired constituents in the apparatus 13, being delivered thereto by pipe 81. Or any part or all of the gas may be diverted from the process by way of pipe 69.

Operation In carrying out the process, fresh charging stock, for example a clean gas oil of about 35" A. P. I. gravity, is introduced through the charging line I and passed through the cracking furnace 3 and reaction chamber 4, wherein the oil is subjected to a cracking operation of any well is also not critical but is suitably in the range of 100 to 400 poundsper square inch, most desirably '-about 200 pounds per square inch. The

resulting cracked products are passed through line 6 into evaporator I and therein separate into vapors and liquid residue in the well known manner. This evaporator is preferably operated at substantially the same pressure as that of the cracking furnace 3, e. "g., 200 pounds per square inch, although it may be operated at considerably lower pressure than that of the cracking furnace if desired. The vapors pass overhead from the evaporator through line 9 into the fractionator I0 and are there subjected to fractionation in the usual well known manner. The fractionated vapors, which have the desired boiling characteristics, pass overhead through line H and condenser l2, the condensate being collected in the receiver l3 in the form of a desired product, for example, gasoline.

In this receiver gas separates from the distillate and passes overhead through line I5 and is forced by action of compressor 20 into the line H, in combination with'any desired quantity of reflux condensate withdrawn from the fractionator I0, and, if desired, additional gas or oil from an external source by way of line H, the combination of condensate and gas passing through the coils'of reverting furnace 18. Ordinarily all of the reflux condensate from the fractionator ID will be passed to the reverting furnace, but if desired a portion may be diverted through line 43. Likewise part of the gas from receiver l3 may be diverted from the process through pipe I2.

In the reverting furnace the introduced products are subjected'to such conditions of temperature and pressure as favor a reaction between the gas and the oil. Preferably high pressures such as 1000 pounds per square inch and moderate temperatures such as 800 to 950 F. will be used in this stage. Under these conditions the naphthenic and the olefinic liquids will react with the olefinic constituents of the gas to make relatively heavy 011. At the same time the parafllnic constituents of the charging stock will be cracked to any value between 200 and 1000 pounds per square inch proving effective. The richer the 7 through content of olefins in the gas from the receiving drum I3 and the higher the concentration of naphthenes in the liquid condensate withdrawn from the fractionator l0, the more active the reaction taking place in the reversion furnace and reaction chamber. With this fact in view adjustmerits of the conditions in the furnace may be made, the higher the content of olefins and/or naphthenes in the gas and liquid oil, respectively, the lower may be the pressure in the cracking zone and also the lower the temperature used for creating the reaction. The cracked and polymerized "products are subjected to further reaction in the'chamber 22, if that reaction chamber be used, and the resulting reacted products are introduced line 24 and control valve 48 into the evaporator 25, which is preferably operated under a pressure substantially the same as that of the evaporator 1. However this pressure may be higher than that of the=evaporator I, if desired, the necessary adjustments being obtained by means of valve 48.

In the evaporator 25 vapors separate from liquid residue, the latter being drawn off through line 26 while the former travel upwardly through the vesel, anynecessary cooling being effected by aid of cooling coils 21 or in any other suitable manner.

The uncondensed vapors pass off from the evaporator 25 through vapor line 28, into fractionator 29, wherein they undergo fractionation in the usual manner, any necessary refluxing action being supplied by means of cooling coil 30 or in any other Well-known manner. The cooling of the top of the evaporator 25 by cooling coil 21 is preferably so regulated that the vapors passing to the fractionator 29 have a boiling characteristiccorresponding to an endpoint of from 700 to 800 F., being in the nature of a heavy gas oil. The reflux condensate collected in the base of the fractionator therefore also has. an endpoint of about 700 to 800 F., while an intermediate condensate in the nature of a light gas oil, iscollected on the trap-out tray 8| and may have an end point of about 500 to 700 F. This light gas oil is preferably recycled to the cracking furnace 3, being mainly paraffinic in nature. The heavy gas oil collected in the base of the farctionator will have been formed mainly by the reaction of gas with heavier products in the reverting furnace l8 and will have a relatively low ratio of hydrogen to carbon. This heavy gas oil, which is suitable for cracking for the production of relativel high anti-knock gasoline, is removed from the base of the fractionator 29 and passed in any desired quantities through the line 36 into the coils of cracking furnace 39, wherein erably through line 40 into the evaporator I, valve 84 being open and valve 85 being closed. In the evaporator 1 the cracked products are subjected to the same treatment as that received by the products from reaction chamber 5, as already described.

Thefractionated vapors, having the desired boiling characteristics, pass off from the'top of fractionator 29 through vapor line 3| and con- 7 natively may be blended with distillate from the receivers l3 and 58, or either of them, by way of lines 86 and 60. Gases may be removed from the receiver 33 by way of pipe 34.

According to a different mode of operation, valve 84 may be closed and valve 85 opened, thereby transferring the cracked products through line 4' into the evaporator 49, wherein vapors separate from liqiuds in the usual manner, the liquids being drawn off through line 50, either for use as fuel oil, or for flashing or any other well known treatment, while the vapors pass through line 5| into the fractionator ill for fractionation therein. In this method of operation.valve 53 is openand valve 552 closed.

If desired the valve 53 may be closed and valve 52 opened, thereby diverting the vapors from evaporator 49 into the fractionator 55, wherein they are fractionated separately from the products in the fractionator III. This method of operation has the advantage that it permits the individual control of -the treatment of cycle stock from the fractionator '5.

Ordinarily all of the reflux condensate from fractionator 55 will be returned by pump 65 through line 64 into line I], for treatment in the reverting furnace l8, but if desired a portion of this reflux condensate, or all of it, may be diverted from' the process through line 66. The vapors pass overhead through line 56 and condenser 51, resulting condensate being collected in receiving drum 58 as a desired product, e. g. gasoline. This gasoline may be drawn off separately through line 59 or blended with the gasoline distillate collected in either of receiving drums l3 and 33, or both of them, by agency of line 60, the necesasry control of flow being effected by the several valves provided, in an abvious manner.

The gas separated from the liquid in receiving drum 58 may be returned directly to the reverting furnace l8 by way of pipe 61, under pressure generated by compressor 68, or may be first freed of undesired constituents,-in apparatus 13. If desired part of this gas, or all of it, may be diverted from the process through valved line 69. The products of the separate cracking of the heavy gas oil in the cracking furnace 39 will be a high formed to a desired liquid oil. In case reformation is to be carried out as a primary step, the cracking furnace 3 and reaction chamber 5 would be operated in such manner as to effect the desired reforming reaction or formation of higher antiknock products. In this case the charging stock would be gasoline of low-anti-knock characteristics. Reforming processes causes the generation of a relatively large amount ofgas and this gas may .be converted to products in the boiling range of the final desired product, by treatment in the manner described hereinbefore. v

.The process described, hereinbefore enables the A reaction vapors and passing saidheavy gas oil condensateavoidance of excessive amounts of coke which I believe result from the reaction of relatively light oleflnic materials, such as ethylene and propylene, with naphthenic and possibly unsaturated liquids, somewhere in the heavy naphtha, kerosene or gas oil boiling range, which occurs in an I ordinary cracking operation where recycling is employed. By preventing recycling or the return of such reflux condensate to the cracking operation, I am able to prevent the undesired reaction of gas and liquid mentioned above, and am able to produce interaction 'of these products in a separate zone, so as to form additional charging stock for a subsequent cracking operation, as well as additional light products in the desired boiling 1 range.

By gas,reversion is meant the reaction between normally gaseous hydrocarbons, particularly gaseous oleflns, and the relatively heavy liquid products of cracking such as cracked tar, cracked gas oil or the like. The exact nature of the reactions is unknown but it is probable that the addition of olefinic sidechains to naphthenic and aromatic compounds proceeds extensively. Because of the variety and complexity of the ring compounds in cracked oils it is obviously impossible to describe these reactions in detail. It is probable that decomposition and recombination catalyst such as aluminum chloride, or other me-.

tallic halide may be used to accelerate the reverting and/or cracking steps, being either passed through the various heating furnaces 'with the stock undergoing treatment, or being introduced into the several'reaction chambers. In case cata lysts are used lower operating temperatures are desirable.

removed from said fractionating zone and passing the mixture through a reverting zone wherein it is subjected to a reverting temperature under a pressure of at least 200 pounds per square inch and reaction between the gas and liquid occurs, passing the resulting products into a separating zone wherein vapors separate froTn liquid residue. fractionally condensing said vapors, independently of said vapors first mentioned, to separate therefrom a heavy gas oil condensate and leave uncondensed relatively light vapors of desired boiling characteristics, separately condensing said light through a second cracking. zone wherein it is raised to a cracking temperature and subjected to cracking and introducing the resulting cracked products into said evaporaating zone.

2. The process of treating hydrocarbon oildesired in the final product, removing the fractionated vapors and condensing them to form a desired distillate, separating fixed gas from the resulting distillate in a gas. separating zone and combining it with condensate formed in the fractionating operaton, passing the resulting mixture through a reverting zone wherein it is subjected to a cracking temperature of from 800 to 950 F. under a pressure of at least 200 pounds per square inch, separating resulting reaction products into vapors and liquid residue, withdrawing said liquid residue from the process, fractionating resulting vapors, independently of said vapors first mentioned, into vapors of desired boiling characteristics and heavy gas oil reflux condensate, passing reflux condensate so formed through a separate cracking zone wherein it is raised to a cracking temperature and subjected to conversion, separating resulting crackedproducts into vapors and liquid residue, withdrawing said residue from the process, passing vapors so separated to a fractionating operation, separate from that in which the vapors from the reversion step are fractionated, wherein fractional condensation thereof occurs, removing the fractionated vapors, condensing them and collecting the condensate asa desired product and combining condensate last mentioned with distillate first mentioned to .form a final desired product.

3. A process in accordance with claim 2 where- V in reflux condensate formed in the last mentioned fractionating operation is returned to the reverting zone for further conversion.

4. A process in accordance with claim 2 wherein in the reverting zone the products are raised to a temperature of about 900 F. under a pressure of about 1000 pounds per square inch.

5. A process in accordance with claim 2 wherein gas formed in the last mentioned fractionating operation is returned to the reverting zone' for further conversion.

6. A process in accordance with claim 2 wherein the fractionation of vapors from the two cracking operations is carried out in a single .fractionating zone.

'7. A process in accordance with claim 1 where"- in an intermediate condensate is separated from the vapors derived from the reverting operation and is recycled to, the first mentioned cracking zone for further conversion.

A process in accordance with claim 1 wherein said fixed gas removed from said distillate is freed of hydrogen and methane before being. combined with. said reflux condensate.

9. The process of treating hydrocarbon oil 1 which .comprises passingfresh charging stock through a cracking zone wherein it is raised to acracking temperature and subjected to conver- 'sion, introducing the resulting cracked products into an evaporating zone wherein vapors separate from liquid residue, passing resulting vapors into a fractionating zone wherein partial condensation occurs, removing fractionated vapors from said zone, condensing the removed vapors and separately collecting resulting distillate, removing fixed gas from said distillate, freeing said gas of hydrogen and methane, combining the hydrogen and methane-free gas with reflux condensate removed from said fractionating zone and passing the mixture through a reverting zone wherein it is subjected to reverting conditions of temperature and pressure and reaction between the gas and liquid occurs, passing the resulting products into a separating zone wherein vapors separate from liquid residue, fractionally con densing sad vapors in a second fractionating zone to separate therefrom a heavy gas oil condensate and leave uncondensed relatively light vapors of desired boiling characterisitics, separately condensing said light vapors and passing said heavy gas oil condensate through a second cracking zone wherein it is raised to ,a cracking temperature and subjected to-cracking and introducing the resulting cracked products into said evaporating zone.

10. The process of treating hydrocarbon oil which comprises passing fresh charging stock through a cracking zonewherein it is raised to a cracking temperature and subjected to conver-' sion, introducing the resulting cracked products into an evaporating zone wherein vapors separate from liquid residue, passing resulting vapors into a fractionating zone wherein partial condensation occurs,'removing fractionated vapors from said zone, condensing the removed vapors and separately collecting resulting distillate, removing fixed gas from said distillate, freeing said gas of hydrogen and methane, combining the hydrogen and methane-free gas with reflux condensate removed from said fractionating zone and passing the niixture through a reverting zone wherein it is subjected to temperatures of from 800 to 950 F., under a pressure of from 200 to 1000 pounds per square inch, and reaction between the gas and liquid occurs, passing the resulting products into a separating zone wherein vapors sepa-. rate from liquid residue, fractionally condensing said vapors to separate therefrom a heavy gas oil condensate and leave uncondensed relatively light vapors of desired bofling characteristics, separately condensing said light vapors and passing said heavy gas oil condensate through a second cracking zone wherein it is raised to a cracking temperature and subjected to cracking and introducing the resulting cracked products.

into said evaporating zone.

11, The process of treating hydrocarbon oil whichi comprises passing fresh charging stock through a cracking zone wherein it is raised to a cracking temperature and subjected to conversion, introducing the resulting cracked products into an evaporating zone wherein vaporsseparate from liquid residue, passing resulting vapors into a fractionating zone wherein partial condensation occurs, removing fractionated vapors from said zone, condensing the removed vapors and separately collecting resulting-distillate, removing fixed gas from saiddistiilate, freeing said gas of hydrogen and methane, combining the hydrogen and methane-free gas with reflux condensate removed from said fractionating zone and passing the mixture through a reverting zone wherein it is subjected to reverting conditions of temperature and pressure and reaction between, the gas and liquid occurs, passing the resulting products into aseparating zone wherein vapors condensate and leave uncondensed relatively" light vapors of desired boiling characteristics, separately condensing said light vapors, returning said intermediate condensate to saidcracking zone first-m'entioned for further conversion, passing said heavy gas oil condensate through a second cracking zone wherein it is raised to a cracking temperature and subjected to cracking and introducing the resulting cracked products into said evaporating zone.

12. The process of treating hydrocarbon oil which comprises passingwfresh charging stock through a cracking zone in the absence of added fixed gas, wherein it is raised to a cracking temperature and subjected to conversion, introducing the resulting cracked products into an evaporating zone wherein vapors separate from liquid residue, passing resulting vapors into a fractionating zone wherein partial condensation occurs,

removing fractionated vapors from said zone,.-

condensing the removed vapors and separately residue, fractionally condensing said vapors in a second fractionating zone to separate therefrom a heavy gas oil condensate and leave uncondensed relatively light vapors of desired boiling characteristics, separately condensing said light vapors and passing said heavy gas oil condensate through a second cracking zone wherein it is raised to a cracking temperature and subjected to cracking,

introducing the resulting cracked products into said evaporating zone, separating fixed gas from said light vapors last-mentioned and combining fixed gas so separated with the said mixture-of gas and reflux condensate for passage through said reverting zone.

13. The process of treating hydrocarbon oil which comprises passing fresh relatively heavy charging stock through a cracking zone wherein it is raised to a cracking temperature and subjected to conversion, introducing the resulting vapors intoa fractionating zone wherein partial condensation occurs, removing fractionated vapors from said zone, condensing the removed vapors and separately collecting resulting distillate, removing fixed gas from said distillate, combining fixed gas so removed with reflux condensate derived from said fractionating zone and passing the mixture through a reverting zone wherein it is subjected to reverting conditions of temperature and pressure and reaction between the gas and liquid occurs, passing the resulting wherein it is raised to a cracking temperature and subjected to conversion, introducing the resulting cracked products into a second evaporating zone wherein vapors separate from liquid residue,

, gas, combining condensate fraction, passing said mixture through withdrawing said liquid'residue from the process and introducing said vapors into said fractionating zone first-mentioned.

14. A process in accordance with claim 13 wherein an intermediate condensate is likewise separated in said second iractionating zone and intermediate condensate so obtained is introduced into said cracking zone first-mentioned for further conversion.

15. A process in accordance with claim 13 wherein the temperature in said reverting zone is from 800 to 950 F. and the pressure therein is in-the neighborhood of 1000 pounds per square inch.

16. The process of treating hydrocarbon oil which comprises passing said oil through a cracking zone and subjecting it to cracking conditions therein, separating the resulting cracked products into vapors and unvaporized residue, fractionating said vapors to separate a higher-boiling fraction as reflux condensate, a lower-boiling fraction as a desired distillate product and flxed said flxed gas with said reflux a reverting zone wherein it is subjected to reverting conditions of temperature and pressure, and reaction between the liquid and gas occurs, separating the resulting reverted products into vapors and residue, vapors to form a high-boiling condensate fraction and a plurality of lower-boiling condensate fractions, returning one of said lower-boiling fractions to said first-mentioned cracking zone and withdrawing the remainder of said lowerboiling fractions as final products of the process.

1'1. The process of treating hydrocarbon oil which comprises passing said 011 through a cracking zone and subjecting it to cracking conditions therein, separating the resulting cracked products into vapors and residue, Iractionating said vapors to separately condense a higher-boiling fraction as reflux condensate, a lower-boiling distillate fraction and fixed gas, treating said fixed gas to remove hydrogen and methane therefrom, combining the hydrogen and methane-tree gas with reflux condensate, passing the mixture through a reverting zone wherein it is subjected to reverting conditions of temperature and pressure, and reaction between the gas and liquid occurs, separating the resulting reverted products into vapors and residue, tractionating said-lastiractionally condensing said" named vapors to separately condenses higherboiling condensate and a plurality of lower-boiling condensate fractions, passing one of said lower-boiling condensates to said cracking zone for further treatment therein and withdrawing the remainder of said lower-boiling fractions as final products oi the process.

18. The process of treating hydrocarbon oil which comprises passing said oil through a cracking zone and subjecting it to cracking conditions therein, separating the resulting cracked products into vapors and residue, fractionating said vapors to separately condense a higher-boiling fraction as reflux condensate, a lower-boiling distillate fraction and fixed gas, combining fixed gas so separated with said reflux condensate, passing said mixture through a reverting zone wherein it is subjected to reverting conditions of temperature and pressure, and reaction between the gases and liquid occurs, separating said resulting products into vapors and residue, fractionating said last-named vapors to separately condense a high-boiling condensate fraction, an intermediate condensate traction and a final distillate traction and passing said intermediate condensate fraction to said cracking zone for further treatment therein.

19. A method of treating hydrocarbon oil which comprises passing said oil through a conversion zone and subjecting it to cracking conditions therein, separating the resulting cracked products into vapors and residue, fractionating the vapors to separately condense a higher-boiling fraction as reflux condensate, a lower-boiling distillate product and fixed gas, treating said gas to separate hydrogen and methane therefrom, thereafter combining the hydrogen and methanefree gas with said reflux condensate, passing said mixture through a reaction zone and subjecting it to conditions of temperature and pressure therein adequate to eflect a recombination of the products passing therethrough, thereafter separating the reaction products into vapors and residue, iractionating the last-named vapors to form a higher-boiling condensate fraction, an inter mediate-fraction and a light distillate traction, returning said intermediate condensate fraction to said first-mentioned cracking zone and withdrawing said light-distillate fraction as a final product of the process.

EAR/OLD V. A'I'WELL. 

